"The moonlight is beautiful tonight" is a famous saying by Natsume Soseki, not from a literary work.
This remark comes from Natsume Tsuishi. At that time, he was an English teacher in a school and asked to translate "i love you" into Japanese. At this time, a student said "I love you", but Natsume Su Shi said that this translation was too tacky. If he expressed it as "the moonlight is so beautiful", the sentence would be more beautiful and more subtle.
About Natsume Soseki:
The real name is Natsume Kinnosuke, born on February 9, 1867, in Tokyo. Natsume's family has a huge power in Edo. Kinnosuke was the youngest son (eighth in the ranking). Since the family had gradually declined before he was born, his parents did not want the youngest son to be born, so he was fostered in the family after his birth. From another family, he was adopted as the adopted son of the Yan Yuan family when he was two years old.
Since then, due to the emotional discord between the adoptive parents and the influence of the adoptive father's work, they have moved frequently. He finally returned to his biological parents when he was ten years old. However, such a happy life was extremely short-lived. His father and brother had always been at odds with him and disapproved of his strong literary ambitions; his mother died of illness when he was fifteen years old, and Kinnosuke was ten years old. At the age of nine, he left home and began his career as a sleepover.